Question

Look at this series $80,10,70,15,60,...$What number should come next?

Answer 1

Step $1$: Identify the pattern.

Given: $80,10,70,15,60,...$

This is an alternate addition and alternate subtraction series.

Observe the first pattern $80,70,60..$

$10$ is subtracted from each number for the next number.

Observe the second pattern $10,15....$

$5$ is added to each number for the next number.

Step $2$: Compute the next number of the series.

Next number of the series$=15+5$

Next number of the series$=20$

Hence, $20$ is the next number of the given series.